MEMS switches with deforming membranes

• US 20060067648A1
• Filed: 08/05/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence, Kothari, Manish
• Granted Patent: US 7,724,993 B2
• Time in Patent Office: Days
• US Class Current: 385/147
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

MEMS switches are formed with membranes or layers that are deformable upon the application of a voltage. In some embodiments, the application of a voltage opens switch contacts.

Claims

1. A microelectromechanical systems (MEMS) switch comprising:

at least first and second terminals;

a first electrode; and

a moveable element having at least a portion thereof forming a second electrode and being moveable in response to applied electric potentials between the second electrode and the first electrode, wherein the first and second terminals are selectively connectable depending on the position of said moveable element, and wherein a voltage below a threshold between the second and the first electrode causes the first and second terminals to be electrically connected.

2. The MEMS switch of claim 1, wherein at least one of said terminals moves with said moveable element.

3. The MEMS switch of claim 1, wherein said moveable element is supported over a substrate, and said first electrode is deposited on said substrate.

4. The MEMS switch of claim 3, wherein said first electrode is covered with an insulating material.

5. The MEMS switch of claim 1, wherein said moveable element is supported over a substrate, and at least one terminal is deposited on said substrate.

6. The MEMS switch of claim 5, wherein said first electrode is deposited on said substrate.

7. The MEMS switch of claim 1, wherein said moveable element comprises a flexible material that is curved in a mechanically relaxed state.

8. The MEMS switch of claim 1, wherein the moveable element comprises a flexible material supporting a rigid plate.

9. The MEMS switch of claim 8, wherein said flexible material comprises a first terminal and the rigid plate comprises a second terminal.

10. The MEMS switch of claim 9, wherein said rigid plate comprises one or more portions extending toward said flexible material and that make contact with one or more terminals in a mechanically relaxed state.

11. The MEMS switch of claim 10, wherein said one or more rigid plate portions directly contacts said flexible material.

12. The MEMS switch of claim 10, wherein said one or more rigid plate portions contact one or more terminals attached to said flexible material.

13. The MEMS switch of claim 8, wherein said rigid plate comprises a contact conductor configured to electrically connect a pair of terminals attached to said flexible material.

14. The MEMS switch of claim 8, wherein said moveable element is supported over a substrate, at least a first terminal is deposited on said substrate, at least a second terminal is attached to said flexible layer, and wherein said rigid plate comprises a third terminal configured to contact said first terminal or said second terminal, or neither terminal, depending on the position of the moveable element.

15. The MEMS switch of claim 1, wherein said moveable element comprises a flexible plate supported from a rigid upper support structure.

16. The MEMS switch of claim 15, wherein at least a portion of the flexible plate comprises the second electrode.

17. The MEMS switch of claim 15, wherein said flexible plate comprises a contact conductor configured to contact terminals attached to said rigid upper support structure.

18. The MEMS switch of claim 17, wherein said flexible plate is supported above a substrate by said upper support structure, wherein a pair of terminals are deposited on said substrate, and wherein said flexible plate comprises a second contact conductor configured to electrically connect said pair of terminals deposited on said substrate.

19. The MEMS switch of claim 1, wherein said moveable element comprises a flexible material supported over a substrate, at least a first terminal is attached to said flexible material on a side opposite to said substrate, and wherein a second terminal is supported in a fixed location adjacent to said first terminal.

20. A microelectromechanical systems (MEMS) switch comprising:

a deformable electrically conductive membrane having first and second major surfaces;

an electrode opposite said first major surface of said membrane;

a first switch terminal movable with said deformable membrane; and

a second switch terminal opposite said second major surface of said membrane such that membrane deformation toward said electrode in response to an applied electric field moves said first switch terminal and said second switch terminal farther apart.

21. The MEMS switch of claim 20, wherein said first switch terminal is said deformable membrane.

22. The MEMS switch of claim 20, wherein said first switch terminal is attached to said deformable membrane through an insulator.

23. A method of opening a microelectromechanical systems (MEMS) switch comprising disconnecting a first switch terminal from an established electrical coupling to a second switch terminal with an electric field.

24. The method of claim 23, wherein said first switch terminal is attached to a deformable membrane that moves in response to said electric field.

25. The method of claim 24, wherein said second switch terminal is fixed relative to said deformable membrane.

26. The method of claim 24, wherein said second switch terminal is also attached to said deformable membrane.

27. The method of claim 23, wherein said first switch terminal and said second switch terminal are fixed, wherein said electric field deforms a flexible plate, and wherein said flexible plate comprises a contact conductor electrically connecting said first and second terminals in the absence of said electric field.

28. A microelectromechanical systems (MEMS) switch comprising:

a movable element comprising at least a first terminal and a first electrode on a first side of a gap;

a second terminal;

a second electrode on a second side of said gap configured to move said movable element based on a potential difference applied to said first and second electrodes to selectively connect said first and second terminals.

29. The MEMS switch of claim 28, wherein said moveable element also comprises said second terminal.

30. The MEMS switch of claim 28, wherein the moveable element comprises a flexible layer and a plate attached to said flexible layer.

31. The MEMS switch of claim 28, wherein the plate comprises a contact conductor configured to selectively make electrical contact with each of the first and second terminals.

32. The MEMS switch of claim 31, wherein the contact conductor comprises protrusions at the points of electrical contact with each of the first and second terminals.

33. The MEMS switch of claim 31, wherein the plate further comprises the first electrode.

34. The MEMS switch of claim 33, wherein the contact conductor is electrically isolated from the first electrode.

35. The MEMS switch of claim 33, wherein the contact conductor and the first electrode are formed as a single conductor.

36. The MEMS switch of claim 28, wherein the first and second terminals are connected when a potential difference less than a threshold is applied.

37. A microelectromechanical systems (MEMS) switch comprising an element movable between first and second positions comprising first and second movable terminals, wherein the first and second movable terminals cooperatively move with the movable element to connect the first and second movable terminals when the element is in the first position and to disconnect the first and second movable terminals when the element is in the second position.

38. The MEMS switch of claim 37, wherein the switch comprises first and second electrodes, and wherein the movement between first and second positions is based on a voltage applied between the first and second electrodes.

39. The MEMS switch of claim 38, wherein the element is in the first position when the applied voltage between the electrodes is below a threshold.

40. A microelectromechanical systems (MEMS) switch comprising:

first and second switch terminals;

means for maintaining electrical contact between said first and second switch terminals when said MEMS switch is in a mechanically relaxed state; and

means for disconnecting the first and second switch terminals by applying a voltage difference to the MEMS switch greater than a threshold.

41. The MEMS switch of claim 40, wherein said means for maintaining electrical contact comprises a flexible layer that maintains a curved configuration in a mechanically relaxed state.

42. The MEMS switch of claim 41, wherein said means for disconnecting comprises at least one electrode associated with said flexible layer, and at least one other electrode.

43. A method of operating a microelectromechanical systems (MEMS) switch comprising:

maintaining electrical contact between first and second switch terminals when said MEMS switch is in a mechanically relaxed state; and

disconnecting the first and second switch terminals by creating an electric field between a pair of electrode surfaces of the MEMS switch.

44. A method of manufacturing a microelectromechanical systems (MEMS) switch comprising:

forming an electrode and an insulator on a substrate;

forming a first sacrificial layer over the insulator;

forming a flexible layer within-plane tension;

forming a first terminal over the flexible layer;

forming a second sacrificial layer;

forming a second terminal over the second sacrificial layer;

forming an upper layer supporting the second terminal; and

removing the first and second sacrificial layers.

45. A MEMS switch manufactured with the method of claim 44.

46. A method of manufacturing a microelectromechanical systems (MEMS) switch comprising:

forming an electrode, and an insulator on a substrate;

forming a plate in a sacrificial layer over the insulator;

forming a layer connected to the plate, wherein the layer or the plate, or both comprise one or more terminals; and

removing the sacrificial layer.

47. The method of claim 46, wherein the plate is flexible.

48. The method of claim 46, wherein the layer is flexible.

49. A microelectromechanical systems (MEMS) switch comprising:

a moveable element on a first side of a gap, the moveable element comprising a contact conductor and a first electrode;

first and second fixed terminals on the first side of the gap;

a second electrode on a second side of the gap configured to move the movable element based on a potential difference applied to the first and second electrodes to selectively connect the first and second terminals, wherein the first and second terminals are connected through said contact conductor when a potential difference less than a threshold is applied between said electrodes.

50. The MEMS switch of claim 49, wherein the contact conductor is electrically isolated from the first electrode.

51. The MEMS switch of claim 49, further comprising third and fourth fixed terminals on the second side of the gap, wherein the second electrode is further configured to move the moveable element so as to electrically connect the third and fourth terminals through a second contact conductor.

52. The MEMS switch of claim 51, wherein said first contact conductor, said second contact conductor, and said electrode are formed from a common conductor.

53. A microelectromechanical systems (MEMS) switch comprising:

a substrate;

a first electrode deposited on said substrate;

a plurality of terminals;

a flexible plate suspended over said electrode and said terminals by an upper support structure, wherein said flexible plate comprises a contact conductor and a second electrode.

54. The MEMS switch of claim 53, wherein said plurality of electrodes are deposited on said substrate.

55. The MEMS switch of claim 54, wherein said flexible plate deforms in response to an applied voltage between said first and second electrodes so as to electrically connect a pair of said terminals through said contact conductor.

56. The MEMS switch of claim 53, wherein said plurality of electrodes are attached to said upper support structure.

57. The MEMS switch of claim 56, wherein said flexible plate deforms in response to an applied voltage between said first and second electrodes so as to electrically disconnect a pair of said terminals.